Example 1.1 CharStack Class

//CharStack.java
public class CharStack { //Class name
// Class Declarations
// Fields:                      (1)
private char[] stackArray; //The array implementing the stack.
private int topOfStack; // The top of the stack

//Constructor: (2)
public CharStack(int capacity) {
  stackArray = new char[capacity];
  topOfStack = -1;
}

//Methods: (3)
public void push(char element) {stackArray[++topOfStack] = element; }
public char pop() {return stackArray[topOfStack--];}
public char peek() {return stackArray[topOfStack];}
public boolean isEmpty() {return topOfStack < 0; }
public boolean isFull() {return topOfStack == stack.Array.lenght -1;}
}

A PROGRAMMERS GUIDE TO JAVA CERTIFICATION: Comprehensive Primer (3rd Edition)